In total shoulder arthroplasty, reproduction of the correct location of the humeral articular surface is critical to reestablishing joint biometrics. Translating this location to the implant is thus of critical importance.
Each shoulder arthroplasty needs to be adapted to the patient's unique combination of soft tissue and bone anatomy. As well, the patient typically has high expectations of the function and durability of the arthroplasty. Thus, the implant and the implant technique must be precise.
In view of this, there has been developed a range of prostheses designed to fit the various sizes and shapes of people's anatomy. For shoulder arthroplasty, a prosthesis with a humerus head has been developed. It has been recognized, though, that the humerus head may need to be eccentrically mounted relative to the prosthesis body in order to cover the exposed, resected humerus head. There has been a problem, however, with the ability to adequately position the eccentric head on the implant in order to meet the needs of every patient. Typically, the eccentric head is positionable in only a few select orientations relative to the eccentricity.
Thus, there is a need for an prosthetic implant that can utilize an eccentric head wherein the eccentric head may be positioned in any number of rotatably eccentric positions.